Dynamic signature verification based on hybrid wavelet-Fourier transform

In this paper, we propose a dynamic signature verification system which integrates hybrid of Discrete Wavelet Transform and Discrete Fourier Transform (DWT-DFT) for feature extraction. In feature matching, Euclidean distance and Enveloped Euclidean distance (EED) (a variant of Euclidean distance) are used. Distances of features are fused into a final score value and used to classify whether a genuine or a forgery signature. A benchmark database, SVC2004 which compose of Task 1 dataset and Task 2 dataset validate the effectiveness of this proposed system. Experimental results reveal a 7.08% EER for skilled forgeries and 2.37% EER of random forgeries in Task 1 dataset; and 8.61% EER for skilled forgeries and 2.05% EER for random forgeries in Task 2 datase

Negative stiffness and enhanced damping of individual multiwalled carbon nanotubes

The mechanical instabilities and viscoelastic response of individual multiwalled carbon nanotubes and nanofibers (MWCNTs/Fs) under uniaxial compression are studied with atomic force microscopy. Specific buckling events are evident by regimes of negative stiffness, i.e., marked drops in force with increasing compression. Uniaxial cyclic loading can be repeatedly executed even in initially postbuckled regimes, where the CNTs/Fs display incremental negative stiffness. Increases in mechanical damping of 145–600 % in these initially postbuckled regimes, as compared to the linear prebuckled regimes, are observed. Increased damping is attributed to frictional energy dissipation of walls in buckled configurations of the MWCNTs/Fs. This represents the extension of the concept of negative stiffness to the scale of nanostructures and opens up possibilities for designing nanocomposites with high stiffness and high damping simultaneously

Outbreak of acute hepatitis C following the use of anti-hepatitis C virus--screened intravenous immunoglobulin therapy

BACKGROUND and AIMS: Hepatitis C virus (HCV) infection has been associated with intravenous (IV) immunoglobulin (Ig), and plasma donations used to prepare IV Ig are now screened to prevent transmission. Thirty-six patients from the United Kingdom received infusions from a batch of anti-HCV antibody-screened intravenous Ig (Gammagard; Baxter Healthcare Ltd., Thetford, Norfolk, England) that was associated with reports of acute hepatitis C outbreak in Europe. The aim of this study was to document the epidemiology of this outbreak. METHODS: Forty-six patients from the United Kingdom treated with Gammagard (34 exposed and 12 unexposed to the batch) returned epidemiological questionnaires. RESULTS: Eighty-two percent of the exposed patients (28 of 34) became positive for HCV RNA. Eighteen percent of the patients (6 of 34) who had infusions with this batch tested negative for HCV RNA, but 2 of the patients had abnormal liver function and subsequently seroconverted to anti-HCV antibody positive. Twenty-seven percent of the patients (9 of 34) developed jaundice, and 79% (27 of 34) had abnormal liver transferase levels. Virus isolates (n=21), including an isolate from the implicated batch, were genotype 1a and virtually identical by sequence analysis of the NS5 region, consistent with transmission from a single source. CONCLUSIONS: Hepatitis C infection can be transmitted by anti-HCV-screened IV Ig. Careful documentation of IV Ig batch numbers and regular biochemical monitoring is recommended for all IV Ig recipients

Mapping of serotype-specific, immunodominant epitopes in the NS-4 region of hepatitis C virus (HCV):use of type-specific peptides to serologically differentiate infections with HCV types 1, 2, and 3

The effect of sequence variability between different types of hepatitis C virus (HCV) on the antigenicity of the NS-4 protein was investigated by epitope mapping and by enzyme-linked immunosorbent assay with branched oligopeptides. Epitope mapping of the region between amino acid residues 1679 and 1768 in the HCV polyprotein revealed two major antigenic regions (1961 to 1708 and 1710 to 1728) that were recognized by antibody elicited upon natural infection of HCV. The antigenic regions were highly variable between variants of HCV, with only 50 to 60% amino acid sequence similarity between types 1, 2, and 3. Although limited serological cross-reactivity between HCV types was detected between peptides, particularly in the first antigenic region of NS-4, type-specific reactivity formed the principal component of the natural humoral immune response to NS-4. Type-specific antibody to particular HCV types was detected in 89% of the samples from anti-HCV-positive blood donors and correlated almost exactly with genotypic analysis of HCV sequences amplified from the samples by polymerase chain reaction. Whereas almost all blood donors appeared to be infected with a single virus type (97%), a higher proportion of samples (40%) from hemophiliacs infected from transfusion of non-heat-inactivated clotting factor contained antibody to two or even all three HCV types, providing evidence that long-term exposure may lead to multiple infection with different variants of HCV

Heavy-metal concentrations in the mangrove snail, nerita lineata and surface sediments collected from Klang River Estuary, Selangor, Malaysia.

The mangrove snail, Nerita lineata, and the surface sediments were collected from the Klang River Estuary, potentially receiving anthropogenic inputs such as domestic, sewage and industrial waste. The snails were divided into three parts, namely soft tissues, operculum and shells and analysed for heavy-metal (Cd, Cu, Fe, Ni, Pb and Zn) concentrations. The total concentrations (μg/g dry weight) of heavy-metals in the surface sediments collected from the four sampling sites ranged from 0.21-1.45, 5.29-53.9, 22121-24175, 14.2-19.5, 30.4-62.3 and 46.4-207 for Cd, Cu, Fe, Ni, Pb and Zn, respectively. The ranges of heavy-metal concentrations (μg/g dry weight) in the shells were 3.45-7.48, 5.54-7.27, 39.8-49.6, 23.8-28.6, 66.3-71.8 and 4.10-7.33 for Cd, Cu, Fe, Ni, Pb and Zn, respectively. The ranges of heavy-metal concentrations (μg/g dry weight) in the operculum were 3.28-5.81, 6.67-11.2, 45.4-68.8, 23.5-24.7, 62.5-66.2 and 14.5-24.9, for Cd, Cu, Fe, Ni, Pb and Zn, respectively. As for the soft tissues, the heavy-metal concentrations (μg/g dry weight) ranges were 1.54-4.47, 17.3-24.4, 627-716, 4.41-5.32, 10.8-43.6 and 87.5-109 for Cd, Cu, Fe, Ni, Pb and Zn, respectively. It was found that the concentrations of Cu, Fe and Zn were higher in the soft tissues while the concentrations of Cd, Ni and Pb were higher in the operculum and shells of the snails

Modeling and Dynamic performance of Energy Storage -Rotary Series Elastic Actuator for Lumbar Support Exoskeleton

The assistive exoskeletons are rapidly being developed to collaborate with humans, and the demand for the safety of human-robot interaction has become more crucial. Series elastic actuators (SEAs) have recently been developed in various fields for a variety of possible advantages, such as providing a safe human-robot interaction, reducing the impacts’ effects, and increasing energy efficiency. However, achieving the good dynamic performances of SEAs is still challenging, especially fulfilling the high bandwidth with good compliance. In this rapidly growing research field, the actuation system involving the storage device combined with the rotary series elastic actuator (ES-RSEA) is being investigated to exploit the biomechanical energy while maintaining compliance features. In this article, the modeling and control design of the energy storage rotary series elastic actuator (ES-RSEA) for the lumbar support exoskeleton is proposed, and its dynamic performances are analyzed. The ES-RSEA was designed based on storing the kinetic energy during the lifting tasks and generating assistive torque while maintaining excellent compliant characteristics. The dynamic performances and characteristics of ES-RSEA are presented in terms of force sensitivity, level of compliance, transmission ratio, and bandwidth. Simulation studies indicate that the actuator can provide excellent dynamic performance through its high bandwidth (12.44 Hz) and high force sensitivity. At the same time, it shows excellent compliance and good torque transmissibility in the low-frequency range. A PID controller can achieve high torque tracking performance and good dynamic response with a root-mean-square (RMS) error of 0.1 N.m. This article demonstrates the excellent performance and characteristics of ES-RSEA to guarantee compliance and high response to prevent injury of undesired human movements

Accumulation and depuration of Cu and Zn in the blood cockle Anadara granosa (Linnaeus) under laboratory conditions.

Studies on the accumulation (4 days of single metal exposure) and depuration (6 days in natural seawater) of Cu and Zn were conducted in the blood cockle Anadara granosa under laboratory conditions. Different rates of accumulation and depuration between the soft and hard tissues probably reflect the different mechanisms of binding and regulation of Cu and Zn between the soft tissues and shells of cockles. At the end of depuration, the concentrations of Cu and Zn in the soft tissues were only 1.71 and 1.75 times higher than prior to the exposure, respectively. Thus, no significant difference was found in the depuration level between Cu and Zn. Hard tissues showed that the levels of Cu and Zn are similar to those before the exposure. This indicated the slow rates of accumulation and depuration in the shells as compared to the soft tissues of A. granosa. The condition index of A. granosa could be used as a potential physiological indicator of metal pollution. The capabilities to accumulate Cu and Zn and to depurate both metals in the soft tissues indicate that A. granosa is a potential biomonitoring organism for its health assessment using the condition index

Correlation of metallothionein expression with apoptosis in nasopharyngeal carcinoma

The expression of metallothionein (MT), an intracellular ubiquitous low molecular weight protein thiol with antioxidant properties, was studied in nasopharyngeal cancer (NPC) and correlated with the apoptotic index. Immunohistochemical staining of randomly selected, formalin-fixed and paraffin-embedded normal and malignant nasopharyngeal tissues were analysed for the expression of MT using the commercially available E9 antibody directed against MT I and MT II isoforms. The corresponding apoptosis labelling indices were evaluated by the TUNEL method. Localization of MT at the ultrastructural level was studied by immunogold labelling. All the tumour sections (17 specimens) showed MT-immunopositivity. A direct correlation between the percentage of MT-positive cells and the staining intensity was noted (P< 0.001; Pearson's r = 0.95). There was absence of cytoplasmic staining and only nuclear staining (with localization in the nucleoplasm) was demonstrated in the tumour cells. In normal epithelium of the nasopharynx, the basal layer was stained. An inverse relationship was observed between the level of MT expression and the apoptotic index in the NPC tissues (P = 0.0059; Pearson's r = –0.6380). The results suggest that overexpression of MT in NPC may protect the tumour cells from entering into the apoptotic process and thereby contribute to tumour expansion. Preferential localization of MT in the nuclei of NPC cells may possibly enhance radioresistance since radiotherapy is known to eradicate tumour cells by free radical-induced apoptosis. © 2000 Cancer Research Campaig

Why some causative ‘give’ constructions develop beyond the passive to also form the unaccusative : evidence from Southern Min dialects

The conference was organized by Linguistic Society of Hong Kong.2011-2012 > Academic research: refereed > Refereed conference paperOther Versio

A dynamic deep sleep stage in Drosophila

Howmight one determine whether simple animals such as flies sleep in stages? Sleep inmammalsis a dynamic process involving different stages of sleep intensity, and these are typically associated with measurable changes in brain activity (Blake and Gerard, 1937; Rechtschaffen and Kales, 1968; Webb and Agnew, 1971). Evidence for different sleep stages in invertebrates remains elusive, even though it has been well established that many invertebrate species require sleep (Campbell and Tobler, 1984; Hendricks et al., 2000; Shaw et al., 2000; Sauer et al., 2003). Here we used electrophysiology and arousal-testing paradigms to show that the fruit fly, Drosophila melanogaster, transitions between deeper and lighter sleep within extended bouts of inactivity, with deeper sleep intensities after15 and30 min of inactivity. As in mammals, the timing and intensity of these dynamic sleep processes in flies is homeostatically regulated and modulated by behavioral experience. Two molecules linked to synaptic plasticity regulate the intensity of the first deep sleep stage. Optogenetic upregulation of cyclic adenosine monophosphate during the day increases sleep intensity at night, whereas loss of function of a molecule involved in synaptic pruning, the fragile-X mental retardation protein, increases sleep intensity during the day. Our results show that sleep is not homogenous in insects, and suggest that waking behavior and the associated synaptic plasticity mechanisms determine the timing and intensity of deep sleep stages in Drosophila